Sedimentation in the Yellow River delta. Part III. Seabed erosion and diapirism in the abandoned subaqueous delta lobe

Abstract

Abstract Historical bathymetry, satellite remote sensing and river discharge data have been used to examine the evolution of an abandoned delta lobe in the northern area of the modern Yellow River delta. Results show three stages of evolution in the subaqueous delta slope after lobe abandonment: (1) rapid erosion stage; (2) slow erosion stage; and (3) erosion–accumulation adjustment stage. According to 1:10,000 bathymetry data and high-resolution seismic profiles, diapirism in the subaqueous abandoned delta lobe is closely related to seabed erosion, which mainly occurs in the middle part of subaqueous delta slope. Diapirism results from the deformation of soft, fine-grained prodeltaic sedimentary stratum when the accumulation body on the soft stratum is removed in rapid erosion stage. The maximum accumulation centre in the delta lobe during growth coincides with the maximum erosion centre in the delta lobe abandonment phase. The diapir body occurs there. Distinguishing from diapirism in the Mississippi delta, three stages of the soft stratum deformation and diapirism are established in the Yellow River delta. The mobile strata and its diapirism are destructive to the offshore engineering facilities.